Bash script not quite matching

Question

I want to cat an apache log and then output the result to a file. I want to match the day/month with the Apache log to the current/previous date, however I seem to be doing this incorrectly.

Sample from apache log: 62.173.92.62 - - [02/Mar/2010:15:46:58 +0000] "GET /img.......

Current script:

cat access_log | grep "\[+%d+/%b" > email.log

Which I was hoping would match the [0/2Mar part of the line, however I am getting nothing in email.log (permissions are ok).

Thanks

Answer 1

grep doesn't work that way; it doesn't care what the current date is, it uses the regular expression you pass it blindly. Use date with an appropriate format to get the value you care about, and use that with grep.

Answer 2

Try something like:

day=`date +%d`
mon=`date +%b`
grep "\[$day/$mon/" access_log

Answer 3

Try this instead, you need to call date and pass its output into the pattern. Also the [ needs to be escaped.

grep "\[$(date +%d/%b/%Y)"

Answer 4

for current

grep "\[$(date +%d/%b/%Y)" file > email.log

for previous

grep "\[$(date +%d/%b/%Y -d 'yesterday')" file > email.log

No need cat.